Several Routine Vaccines May Lower Alzheimer's Risk
Michelle Milliken
There are plenty of standard vaccines we get throughout our lives, including those for measles, mumps, rubella, tetanus, diphtheria, and Hepatitis B. A new study finds that not only do some of these shots help prevent the disease they target, they may also help stave off cognitive decline.
Research recently published in the Journal of Alzheimer’s Disease investigated how routine vaccines impact the risk of developing Alzheimer’s disease in older adults. After examining the vaccination and cognitive health history of more than 1.6 million people, the researchers found that there was a lower risk of Alzheimer’s when a person was vaccinated for tetanus and diphtheria, with or without pertussis (Tdap or Td); herpes zoster or shingles; and pneumococcus.
Past research by this team has linked the flu shot with a decreased risk of Alzheimer’s, so the study builds on the evidence of the cognitive benefits of vaccines.
Dr. Paul E. Schulz, senior author and director of the Neurocognitive Disorders Center at UTHealth Houston’s McGovern Medical School, says, “We were wondering whether the influenza finding was specific to the flu vaccine. This data revealed that several additional adult vaccines were also associated with a reduction in the risk of Alzheimer’s. We and others hypothesize that the immune system is responsible for causing brain cell dysfunction in Alzheimer’s. The findings suggest to us that vaccination is having a more general effect on the immune system that is reducing the risk for developing Alzheimer’s.”
To study the link between the two, the researchers looked at data from adults 65 and older over an eight-year period, focusing on the differences between patients who had, and had not, received the Tdap/Td, shingles, and pneumococcal vaccines.
They found that recipients of the Tdap/Td vaccine were 30% less likely to develop Alzheimer’s compared with their vaccine-free counterparts, while shingles and pneumococcal vaccines were linked with a 25% and 27% lower risk, respectively.
Why the link? The researchers have a few theories.
Study co-author Dr. Avram Bukhbinder says, “We hypothesize that the reduced risk of Alzheimer’s disease associated with vaccines is likely due to a combination of mechanisms. Vaccines may change how the immune system responds to the build-up of toxic proteins that contribute to Alzheimer’s disease, such as by enhancing the efficiency of immune cells at clearing the toxic proteins or by ‘honing’ the immune response to these proteins so that ‘collateral damage’ to nearby healthy brain cells is decreased. Of course, these vaccines protect against infections like shingles, which can contribute to neuroinflammation.”
The team says their findings suggest that it’s important for patients to have easy access to routine adult vaccines, including as a possible preventive measure for Alzheimer’s.
The findings also reflect past research indicating that the varicella zoster virus, which causes shingles, and herpes simplex virus type 1 can increase the risk of Alzheimer’s. You can read more about that here.
